1. Technical Field
The present invention relates to an inflatable vehicle occupant protection system. In particular, the present invention relates to a dual stage air bag inflator having a toroidal chamber for storing a mixture of gases including a combustible gas.
2. Description of the Prior Art
Known structures for inflating a vehicle air bag typically include a container for solid ignitable material, inflation fluid in the form of air or other gas, or inflation fluid with a relatively small amount of a solid ignitable material. The known structures are actuatable to inflate air bags upon the occurrence of an event requiring inflation of the air bags, such as a collision of a predetermined severity. In one type of structure, the solid ignitable material is ignited to generate a gas for inflating the air bag. In another type of structure, the stored inflation fluid is discharged from the container for inflating the air bag. In yet another type of structure, the relatively small amount of ignitable material is ignited to produce combustion products which heat the stored inflation fluid as the inflation fluid is discharged from the container for inflating the air bag.
U.S. Pat. No. 5,348,344 discloses another type of air bag inflator. The inflator stores a gas mixture including a noncombustible inflation gas portion and a combustible gas portion. An igniter is energized to ignite the combustible gas portion which heats and pressurizes the inflation gas portion. The heated and pressurized inflation gas portion is directed into an air bag to inflate the air bag.